INTERACTION OF TRIPLEN HARMONICS PRODUCED BY SYNCHRONOUS GENERATOR WHEN CONNECTED WITH RECTIFIER

The third harmonic has caused much power quality problem in the neutral of distribution system. Salient pole synchronous generator and non-linear load have been known and recognized as the source of triplen harmonics. Main purpose of this project is to study the characteristics of triplen harmonics current produced by synchronous generator when connected with rectifier and various types of loads. This research is done by shunt connecting full bridge rectifier between synchronous generator and load. The measurement of third harmonics is taken at generator, rectifier and load to see the characteristics of the third harmonics. In this research, the phase angle of the third harmonics is also taken into account. When full bridge rectifier is shunt connected between synchronous generator and load, the third harmonic current at rectifier and load are actually coming from the generator that depend on the load impedance and phase angle. The third harmonic current of the generator is the vector sum of both load and rectifier third harmonic current for generator load with rectifier connection. In parallel operation of synchronous generator with rectifier and load, the third harmonic current at generator does not affected by rectifier due to the delta of transformer blocking the third harmonic from flowing to the load and rectifier. However, the third harmonic current recorded at rectifier is due to the rectifier drawing the current in non-sinusoidal form from the star side of transformer. From overall findings of the project, the rectifier affects the third harmonic current level at generator when operated in island mode with and without the existence of transformer. However, it does not affect the third harmonic currents level at generator in parallel operation.